Electrical properties of individual single-crystalline gallium phosphide nanowires with an outer oxide shell

dddHigh-quality single-crystalline GaP nanowires were grown by a simple vapour deposition method and their electrical and opto-electric transport properties were studied. Structural studies showed that the GaP nanowires consisted of a core-shell structure with a single-crystalline GaP core and an outer gallium oxide (GaOx) layer of thickness similar to6 nm. The individual GaP nanowires exhibited n-type field effects with an on/off ratio as high as 1 05 and their carrier mobilities are in the range of about 10-22 cm(2) V-1 s(-1) at room temperature. When the devices were exposed to an ultraviolet (UV) light source, the current in the nanowires increased abruptly to more than 103 times, and this was possibly due to carrier generation in the nanowires and de-adsorption of adsorbed O-2- ions on the GaOx surface shell. The nanowires also showed good reversible switching actions between the high- and low-resistance states.